Abstract: An efficient and reliable method that identifies possible reference sites in an image is disclosed. The method emphasizes customizing the identification of reference sites for each application by providing for initialization of various parameters, such as the size of the reference site. The method then uses a series of measurable parameters to filter possible reference sites in the image and produces and ordered set of possible reference sites. The highest-ranking site of the ordered set is expected to be chosen as the reference site for production. A preferred implementation is disclosed that uses multi-resolution images to enhance efficiency of the identification and that specifically measures the symmetry, orthogonality and uniqueness of the windows.

Abstract: A method of calibrating an electrophotographic machine having an image bearing surface includes depositing a toner patch on the image-bearing surface. The toner patch has a nominal coverage that varies substantially continuously from end to end. Light is emitted onto a selected one of the areas of the toner patch. An amount of light that is reflected off of the selected one area of the toner patch is measured. The emitting and measuring steps are repeated for each of a plurality of different areas of the toner patch. At least one electrophotographic condition is adjusted. The adjusting is dependent upon the measuring steps.

Abstract: Defect and maintenance detection for an image capture device (ICD) capable of distinguishing between a defect in the ICD and one on the imaged object. The defect detection system includes, inter alia: a value combiner that combines a brightest image video value for each sensing element of the ICD experiencing the imaged object with a corresponding stored device video value to create a combined value for each image video value; and a defect determinator determines the presence of a defect(s) by comparing the combined values to a defect threshold. The maintenance detection system includes a determinator that determines when maintenance is required based on whether a single image is considered defective or whether a number of consecutive defective images have been created. Device video values are updated sluggishly according to corresponding image video values.

Abstract: An evolutionary algorithm evolves alternative architectures and parameters for an image classification system. In a preferred embodiment, a learning system is employed, and during the training period of the learning system, the architecture of the learning system is evolved so as to create a learning system that is well suited to the particular classification problem set. In like manner, other parameters of the image classification system are evolved by the evolutionary algorithm, including those that effect image characterization, learning, and classification. An initial set of parameters and architectures are used to create a set of trial classification systems. A number of pre-classified evaluation images are then applied to each system, and each system's resultant classifications for each test case is compared to the proper classification of each test case. Subsequent trial classification systems are evolved based upon the parameters and architecture of the better performing classification systems.

Abstract: A method for opto-electronic scanning, by pixel and by line, of screened master photographic images with a sensing device. From the actual scanning, at least one master photographic image area that contains the grid scale is detected in the screened master photographic image. Subsequently, the picture values present in the local area of the detected grid scale area of the master photographic image are transferred by Fourier transformation to the frequency range as a spatial frequency spectrum, and, from the spatial frequency spectrum, the screen ruling and raster angle of the raster of the master photographic image are determined. For the determined raster angle and the determined screen rulings of the grid scale of the master photographic image, the optimal scan frequencies for Moiré-free scanning are determined from the spatial frequency spectrum.

Abstract: An image scanning apparatus with scan-starting point positioning function comprising a casing, a carriage and a calibration sheet is provided. Of which, the casing comprises a scan-platform used to place documents to be scanned, while the calibration sheet, which is fixed to the inner surface of the carriage and lies between the home line of the carriage and the upper wider margin of the scan-platform, comprises a hollowed-out mark completed through a punch-cutting manufacturing process. The mark can be defined using a predefined function set and has a reference point. After the carriage has moved to a scan line, the reference point can be located according to the intersection points between the mark scanned and the scan line accompanied by the predefined function set of the mark. Of which, the calibration sheet and the inner surface of the casing are of different levels of brightness.

Abstract: A color copying machine for outputting a draft image has a preparing unit for preparing calibration data containing its scanner's calibration patterns to be output from a printer of the color copying machine, and a correcting unit for correcting the draft image input from the scanner of the color copying machine based on the calibration data prepared by the preparing unit. When the color copying machine, which input an image, is needed to be different from the color copying machine that outputs the image, a plurality of the color copying machines of the present invention, which are connected together, may be used to improve the color reproducibility of printed materials.

Abstract: An image scanning system and method for a scanner that stores calibration parameters of the scanner in the memory of a control module or a selected system file. The image capturing element directly performs image capturing on the scanning object and through the calibration parameters to perform compensation and calibration process for the captured image such that the scanner needs no pre-scanning or only one pre-scanning to obtain the calibration parameter from empirical value thereby to directly perform image scanning on the scanning object.

Abstract: In a process for calibrating an optoelectronic scanning member of a scanner which scans an image point by point and line by line and converts the modulated scanning light into image values in a light/voltage converter, converter densities are first determined and stored as a converter density table depending on different degrees of amplification of the light/voltage converter. The densities of the scanning diaphragms and grey filters used are also determined and stored as diaphragm density and grey filter density tables. A scanner-specific calibration is carried out with a reference diaphragm by adjusting the degree of amplification so that the image value corresponds to a predetermined white level. When a document-specific calibration is later carried out, the required amplification is automatically determined from the stored density tables and the white point density of the document in question. The light/voltage converter is then adjusted accordingly.

Abstract: An electrophotographic machine has at least two printing modes, with each printing mode having a respective printing density. A method of calibrating the electrophotographic machine includes depositing at least one toner patch on an image-bearing surface. The depositing is performed in a first of the printing modes. Light is emitted onto the at least one toner patch. An amount of light that is reflected off of the at least one toner patch is measured. At least one first electrophotographic condition for the first printing mode is adjusted dependent upon the measuring step. At least one second electrophotographic condition is adjusted for a second of the printing modes. The adjusting of the at least one second electrophotographic condition is dependent upon the measuring step.

Abstract: A focus calibrating method for an image scanning device by testing a focus chart is disclosed. The focus chart has a base sheet and a plurality of black bars with different widths arranged in parallel on the base sheet and spaced from each others. The focus chart is adhered on a bottom surface of a top panel supporting the document positioning plate of the scanner and disposed facing the optical scanning module of the scanner. The focus method includes steps of moving the optical scanning module to read the image data of the focus chart, calculating a focal length value of the image data of the focus chart, judging whether a predetermined optimal focal length is reached or not according to the calculated focal length value, repeatedly moving the optical scanning module with respect to the focus chart to adjust the focal length until the optimal focal length is reached.

Abstract: A facsimile communication system, having a hierarchical system, comprises a central service center as the highest hierarchy, several local service centers as an intermediate hierarchy, plural facsimiles as the lowest hierarchy. The central service center manages the local service centers and fax via the local service centers through a telephone network by the pictorial communication and data communication. A user of a facsimile fills up a support service application by marking YES/NO or wiring desired data. The central service center receives the application and inputs the data to store and send the data to a local service center in charge of the facsimile.

Abstract: An optical reading head system has a calibrated pixel output, consisting of a discrete value for each of a plurality of pixels. The system has a scanning station with an exposure region that includes an image region and a detector including an array of photosensitive sites that sense reflected light from the exposure region during a detector exposure period to generate a pixel output profile of the image region. There are a plurality of light sources for lighting the exposure region. Each light source emits an individually controllable amount of light to the exposure region during a detector exposure period such that the system's pixel output is acceptably calibrated. A calibration medium is supplied with a calibration region, and a target pixel output profile is defined for the calibration. The individually controllable light sources are adjusted to make the pixel output profile acceptably within range of the target pixel output profile.

Abstract: Method and apparatus for aligning more than two fragments of an image to assemble the image while providing high alignment quality between each pair of overlapping image fragments. Image registration operations are performed rapidly. The disclosed method and apparatus finds application in, for example, scanning, copying, and facsimile transmission of large format documents.

Abstract: An error detection apparatus and method for use with engravers, such as gravure engravers. An error value E corresponding to the difference between a set of predetermined setup parameters and actual measurement of a portion of an engraved area on the cylinder is determined. The error value E is then used to adjust the engraver to engrave an actual cut or etch in accordance with the set of predetermined setup parameters. The error detection and correction system is suitable for providing a closed-loop system for engraving a cylinder. The apparatus and method may be used during initial setup or during normal operation of the engraver.

Abstract: An image forming apparatus includes: an image reading device for reading an original document image to form the image in a copying mode; a modem device for decoding data sent from a public network; a first memory for registering telephone identification information for a remote station; a detector for detecting a telephone identification provided with a caller identification service of a communication enterprise; and a controller for controlling the modem device, realizing a first communication mode for receiving facsimile data to form the image in a facsimile mode, or a second communication mode for diagnosis of the apparatus and for setting control information of the apparatus from the remote station through the modem device. The controller realizes the first communication mode when the telephone identification does not coincide with the registered telephone identification, and realizes the second communication mode when the telephone identification coincides with the registered telephone identification.

Abstract: A data communication apparatus such as a facsimile is constructed by a communication unit to transmit and receive data, an output unit such as a printer to output the data received by the communication unit, and a connection unit such as an LAN to connect one or more external apparatuses. Data of an output-capable ability of the output unit and data of an output-capable ability of the external apparatus connected through the connection unit are notified to a communication apparatus on the partner side by the communication unit. The ability data indicates an image size and a resolution of image data that can be outputted by the output unit and/or the external apparatus. The data communication apparatus also has a transfer unit to transfer the data received by the communication unit to the external apparatus connected to the LAN. When the image size and resolution of the received image data exceed the output-capable ability of the output unit, the transfer unit transfers the received data.

Abstract: A method for enhancing scan resolution, suitable for the application of a scanner with a sensor. The range that a detecting cell in the sensor can detect is the original pixels with a predetermined number. The scanned result of the detecting cell is called the scanned pixels. In the method for enhancing scan resolution, a smooth image region is scanned to obtain a smooth image data. The smooth image region includes at least the above original pixels with the predetermined number. The smooth image region has a uniform brightness. According to the smooth image data, the scanned pixels obtained from scanning the document are processed.

Abstract: The invention produces a document-image reading device that can analyze a speed fluctuation state of a scanner when scanning an image in the feed direction by separately extracting speed fluctuation components by determining a change in density of references scale lines; and, on the basis of the analysis result, prevents the occurrence of an image blur that can result from unstable factors of a driving mechanism of the device. The document-image reading device, which reads document image data at a specified time interval given by a reference clock signal, comprises an image sensor that can read a document image while the document-image reading device or the document moves in the feed direction. Additionally, the document-image reading device includes a chart reader for reading a reference chart portion having alternations of high-density and low-density divisions that are arranged one after another at a distance interval equal to the least pitch readable by the document-image reading device.

Abstract: It is decided whether or not a light exposure lamp 5 burns out by comparing a light receiving output of a CCD 10 involved when a light exposing position of a light exposure lamp 5 corresponds to a white color reference sheet 13 with an initially set value.

Abstract: An apparatus in a linear complementary metal-oxide-semiconductor sensor for dark calibration comprises a plurality of exposure control devices used for controlling corresponding a first electrical access to a photocell and located between the corresponding photocell and in common a voltage line. In the present invention, the exposure control devices comprise on/off switches that can enable and disable the first electrical accesses. The apparatus is applied with a method for dark calibration of a scanner with a linear sensor. The method comprises disabling a plurality of electrical connections between a plurality of corresponding photocells and in common a voltage line in said linear sensor, and thereafter exposing said photocells.

Abstract: A method and system updates individualized calibrated tone-reproduction curves. A plurality of predetermined stored calibrated tone-reproduction curves are used, each predetermined stored calibrated tone-reproduction curve corresponding to a distinct media type and halftone type combination along with a plurality of predetermined relationships between each stored calibrated tone-reproduction curve and a reference media type and reference halftone type combination. A new tone-reproduction curve corresponding to a reference media type and reference halftone type combination calibration operation is generated, and each predetermined stored calibrated tone-reproduction curves based on the newly generated tone-reproduction curve corresponding to the reference media type and reference halftone type combination and the plurality of predetermined relationships between each stored calibrated tone-reproduction curve and the reference media type and reference halftone type combination is updated.

Abstract: A method and system updates individualized calibrated tone-reproduction curves. A plurality of predetermined stored calibrated tone-reproduction curves are used, each predetermined stored calibrated tone-reproduction curve corresponding to a distinct media type and halftone type combination along with a plurality of predetermined relationships between each stored calibrated tone-reproduction curve and a reference media type and reference halftone type combination. A new tone-reproduction curve corresponding to a reference media type and reference halftone type combination calibration operation is generated, and each predetermined stored calibrated tone-reproduction curves based on the newly generated tone-reproduction curve corresponding to the reference media type and reference halftone type combination and the plurality of predetermined relationships between each stored calibrated tone-reproduction curve and the reference media type and reference halftone type combination is updated.

Abstract: A process for the reduction of artefacts during the reproduction of an image based on image data and having a plurality of image points, by a specific image reproducing device is disclosed, whereby the image points have appearance properties, the process including the following steps: device characteristics which describe the appearance properties of image points produced by the specific image reproducing device in answer to image data and describe the dependence of the appearance properties on the position assigned to the image data, are provided or input, reproduction image data are input, and the image data corrected based on the device characteristics and depending on the positions assigned to the image data.

Abstract: A series of registration marks are printed on a color patch sheet or on a series of color patch sheets used for calibrating a color image reproduction system. These registration marks will be printed by a printer under control of an image processing unit and thereafter scanned by a scanner and interpreted by the image processing unit. For example, the registration marks may be small, black, rectangular blocks arranged at one or all of the top, bottom and sides of the page. These marks provide a variety of color patch information including the horizontal and vertical start and end points of the color patch array, the horizontal width and vertical height of the color patches, the page number of the color patch sheet and print mode of the printer when the color patches are printed, and an indication of the bottom of the color patch sheet.

Abstract: An information processing apparatus, a printing apparatus, an information processing method and a printing method can print high quality images without lowering throughput by correcting density variations to within a range where they can hardly be perceived by the human eye as stripes or unevenness. With this invention, a print head having a plurality of nozzles capable of ejecting ink is used to print a test pattern based on image data with a predetermined gradation level. Then, based on read data of the test pattern, a temporary correction value &agr;′[N] is calculated which will made the print density of rasters corresponding to each of the plurality of nozzles constant. The temporary correction value &agr;40 [N] is limited by the upper limit &agr;U and the lower limit &agr;L so that it is limited to within a range between &agr;U and &agr;L.

Abstract: An optical calibration plate and the assembling method for the same are disclosed. The optical calibration plate is assembled on a cover of an optical apparatus, the cover has a clamping means and the optical calibration plate is locked on the clamping means. The assembling method comprises following steps: (1) clamping one side of the optical calibration plate on a clamping means of a cover of an optical apparatus; and (2) clamping another side of the optical calibration plate on another clamping means of the cover. The optical calibration plate has less contamination because the operator will not touch the optical calibration and the processing time and cost are reduced.

Abstract: An image-forming apparatus processes image signals based on a predetermined gradation-converting curve. The predetermined gradation-converting curve includes at least one of: a first gradation in which a maximum absolute-value of a difference between a lightness gradation curve and its smoothed curve in a range of about {fraction (1/10)} of its gradation number is not greater than 1; a second gradation in which a maximum absolute-value of first-order differential values of a difference curve between a lightness gradation curve and its smoothed curve in a range of about {fraction (1/10)} of its gradation number is not greater than 100; and a third gradation, in which a maximum absolute-value of first-order differential values of a difference curve between a first smoothed curve in a range of about {fraction (1/100)} of a gradation number and a second smoothed curve in a range of about {fraction (1/10)} of a gradation number, is not greater than 100.

Abstract: A method of calculating shading correction coefficients for an imaging system from a non-uniform and unknown calibration standard is disclosed. The standard may be of two or more dimensions and divided into several parts. The standard is imaged in an initial position to obtain a set of initial image intensities corresponding to defined regions on the standard. The standard is then repositioned and imaged in one additional re-arrangement for each of its dimensions. For each re-arrangement, an set of re-arranged image intensities are obtained. The initial and re-arranged image intensities are combined mathematically to determine a shading error for each of the defined regions, based on a value selected for one or more of the shading errors. The shading errors are inverted to provide a set of shading correction coefficients. Either of the shading errors or the shading correction coefficients may be normalized to eliminate the effect of the selected value.

Abstract: A facsimile module self-diagnostic system is provided that can detect a failure occurring in the transmission-side demodulation circuit or in the reception-side re-modulation circuit in a facsimile module. A test facsimle signal generation circuit (10) is provided on the transmission side of the facsimile module. A test facsimile signal judgement circuit (25) is provided on the reception side of the facsimile module. In a test facsimile signal judgement zone, the test facsimile signal judgement circuit (25) inspects a test DCS (Digital Command Signal) signal at the first stage and inspects a test TCF (Training Check) signal at the second stage.

Abstract: A facsimile communication system includes a calling and a called facsimile machine connected via a communication network. Each of the facsimile machines has a timer value representing a maximum allowable response time for a response signal relative to a signal transmitted to the counterpart facsimile machine. Using the timer value, each of the facsimile machines monitors whether the response signal is received from the counterpart facsimile machine within the timer value. If the response signal is not received within the timer value, retransmission of the transmitted signal is required. The called facsimile machine transmits all timer value change information for increasing the timer value to the calling facsimile machine. The calling facsimile machine selects the optimum timer value change information within the range of the timer value change information received from the called facsimile machine, and transmits the selected timer value change information to the called facsimile machine.

Abstract: A method and an apparatus for obtaining a magnification error in a first direction for an image scanning apparatus is disclosed. The method includes steps of (a) providing a marking pattern having a particular length in the first direction, (b) scanning the marking pattern to obtain a scanning length in the first direction, and (c) calculating the magnification error in the first direction from scanning length and the particular length.

Abstract: A system and method for correcting distortions that occur in image capture systems is disclosed. The present invention in some preferred embodiments includes provisions to correct or change magnification differences for all causes including position errors in zoom lens positioning mechanisms as well as those caused by chromatic aberration, CCD alignment errors, lens distortion off center variations, pincushion/barrel lens distortion, magnification distortions, camera and lens misalignment errors, and lighting variations (including flash-to-flash illumination variations). A significant feature of the present invention in contrast with the prior art is that with the use of a movable calibration plate in the present invention it is possible to image capture both the calibration plate and the input object image in a single image capture, thus permitting simultaneous compensation for a variety of lighting and illumination variations not possible with the prior art.

Abstract: A duplex scanner capable of calibrating the two-sided documents comprises an automatic document feeder (ADF), an upper carriage and an upper calibration paper. The upper carriage is installed in the ADF and the upper calibration paper is installed under the upper carriage. Alternatively, the upper carriage is movable installed in the ADF while the upper calibration paper is fixed in the duplex scanner and corresponding to the upper carriage. Before image scanning, the relative motion between the upper carriage and the first calibration paper is generated for calibrating the light beam information. According to the invention, the effects of the contaminated upper calibration paper for the calibration of the light beam information can be reduced, and the quality of the scanning image is greatly enhanced.

Abstract: Density calibration for a printer is achieved using a standard grey scale vignette master and a stored gray scale vignette image that the printer operator can invoke from the operator panel of a printer. The vignette image provides a precalibrated scale that is used in conjunction with the “standard ”image to determine the proper optical density. The density is then set by the printer control panel based upon the value obtained by visually matching the two grey scale vignettes.

Abstract: A printer having at least first and second print heads, each with independently controllable print resolution, controllably prints text data with a first resolution and non-text data with a second resolution. Preferably, the printer is comprised by first and second ink jet print heads which eject ink droplets through plural nozzles based on digital data stored in a print buffer. Resolution is controlled by controlling ink droplet size, nozzle ejection sequence, and readout order from the print buffer, all with droplet size, ejection sequence and readout order being controlled independently for each print head. A user interface allows a user to control resolution of text and non-text data independently.

Abstract: Wavefront information for an optical system is calculated based on the intensity of an image of a plurality of gratings having different periods and orientations taken from at least two different planes a predetermined distance apart. The image of a plurality of gratings having different spatial frequencies or periods and orientations, the location of which are precisely known, are imaged in a nominal focal plane of the optical system, and, preferably, in two additional planes displaced a predetermined distance from the nominal focal plane. The phase shift, if any, from a fundamental frequency of the image intensity, is determined based on the known location of the grating and the grating image intensity. The grating image intensity is detected and measured in a first detection plane in a nominal focal plane and in a second detection plane a predetermined distance from the nominal focal plane. From these measurements wavefront information is calculated.

Abstract: In an image output device a test chart 18 including tests charts 6 of each color is used, and a tone correction table is calculated. The test charts 6 are patterned in a checkered pattern, each including continuous areas 10 in which the tones increase in steps and reference areas 11 for comparison with the continuous areas 10. The reference areas 11 are formed of white ground of paper in a highlight proof part 7, a solid pattern with a maximum density in a shadow proof part 8, and halftone dot-concentrated or line screens with a lower resolution than in the continuous areas in a middle proof part 9. Tone correction values are calculated from characteristic values of the highlight, shadow and middle parts, obtained from visual data of the test chart 18.

Abstract: An image processor includes an operation panel at which color adjustments for image data are set. A generation device generates a pattern signal which represents a state related to the set color and image data representing a test image. A processor processes the image data representing the test image on the basis of the set color adjustment. The processed image data and the pattern signal are then output by an output device such as a color printer.

Abstract: A peak value of readings of a reference plate is calculated by a peak value calculation means. The peak value is stored by a storage means. An average value of the readings of the reference plate is calculated by an average value calculation means. Difference data between the peak value and the average value is calculated by a difference data calculation means. A variable correction coefficient is set by a correction coefficient setting means through use of the difference data and the peak value as shading correction reference data. Readings of an document image is corrected by a correction means through use of the correction coefficient. Thereby, dispersion of document image readings in shading correction is decreased.

Abstract: An error detection apparatus and method for use with engravers, such as gravure engravers. An error value E corresponding to the difference between a set of predetermined setup parameters and actual measurement of a portion of an engraved area on the cylinder is determined. The error value E is then used to adjust the engraver to engrave an actual cut or etch in accordance with the set of predetermined setup parameters. Advantageously, an error detection and correction system is suitable for providing a closed-loop system for engraving a cylinder. The apparatus and method may be used during initial setup or during normal operation of the engraver. Other features include an autofocus routine to facilitate the auto-focus procedure. Also, image processing is further enhanced by gap filling, discontinuity removal, and light calibration methods which may be used alone, in combination with each other, or in combination with the automatic focus system and/or automatic shoe system.

Abstract: A method of making a photoprocessing reference image control tool photograph includes the steps of recording an image onto film of a first type, reading digital image data from the film, recording images of a color chart onto film of the first type and film of a second type, reading the color chart images to obtain first and second digital chart image data, determining a correspondence relationship defining correspondence of the digital values, converting the digital image data using the correspondence relationship to obtain converted image data, and reproducing the converted image data to obtain a photoprocessing reference image control tool photograph.

Abstract: A parameter input section inputs, as parameters, the luminance difference between a to-be-recognized object P and its background, conveyance conditions, etc. An endpoint detecting section uses the parameters to detect a plurality of border points between the object P and the background, without being influenced by external noise or a stain on the object P. A length detecting section detects vertical and horizontal lengths of the object P, and an entire-object position determining section determines the position of the entire object P using the lengths detected by the section. A recognizing section compares an image input by an image input section, with reference image data stored in a reference image data memory, thereby recognizing the object P.

Abstract: The image forming apparatus includes: an image data input section for reading a document as image data; a target value memory section for storing a target value of an input/output characteristic value when a reference document is read; a comparator for comparing the image data of the reference document and the target value so as to create a new input/output characteristic value; a fixed value memory section for storing a difference in input/output characteristic values as a fixed value between an original document and a copy document; and an adder for adding the fixed value to the image data of the reference document so as to output a resultant value to the comparator. By the provision of the fixed value memory section and the adder, the image forming apparatus can set a plurality of input/output characteristic values by reading the reference document once, thus reducing time for the procedure of setting the respective input/output characteristic values.

Abstract: An automatic scanner calibration method and apparatus is disclosed in which a calibrated target, such as a Kodak® gray strip, is attached to a scanning surface of a scanner. The target is thin and has a width or length of platen of a scanner. During a normal scan, the calibration target area can be ignored or scanned depending on user selection. If the strip is scanned, then the resulting information is used to calibrate the scanner automatically. Such calibration is more accurate than an older in time or preset default calibration Another embodiment of the invention actuates a print of a printer calibration target on a printer on a scheduled basis. Thereafter, the user can take the printer calibration target and place it on the scanner and perform a calibration of a scanner/printer system.

Abstract: A method embodiment of the invention tests revisions made to printer graphics interpreter software. A test suite of POSTSCRIPT, PCL, or other high-level printer language is input to a production version of a printer's internal interpreter software. A first bit-map is generated by the interpreter that is normally used to control each pixel in the printing of a page. The same test suite is fed to a work-in-progress revision of the printer's internal interpreter software. A second bit-map is generated. The first and second bit-maps are subtracted from one another. A difference bit-map is inspected. If only minor shifts of objects are noted, or if no differences at all are apparent, the work-in-progress revision is accepted as the new production standard. The second bit-map is used to replace the first. Otherwise, the work-in-progress revision of the printer's internal interpreter software is reworked to correct the printing interpretation errors it was making.

Abstract: Watermark and pattern detection can be improved by compensating for artifacts introduced into an image by a printer and/or scanner through which the image has passed. With the present invention, prior to watermark or pattern detection, the image is filtered or modified to compensate for artifacts introduced by the printer and/or scanner. Some scanners automatically compensate for artifacts introduced by the scanner by using a calibrated tone map. The automatic compensation provides an image from which, a watermark can be easily read. However, generally the user is provided with an interface which can be used to change certain parameters such contrast and intensity. The changes made by the user change the compensation (i.e. the tone map) applied to the image. If the user changes the compensation applied to the image it can affect the ability to read the watermark.

Abstract: A method for developing calibration curves and for calibrating a halftone imaging device to reproduce on an imaging medium gray scale values equal to input gray scale values entered in said imaging device. According to this method a calibration function representing a linear change in reproduced halftone dot size on said imaging medium as a function of input halftone dot size is developed by using the device to reproduce on an imaging medium at least two test input dot values representing two different % halftone dot sizes and determining a linear change between the input and the reproduced halftone dot sizes. The dot growth is used to predict dot changes for other % halftone dots and thus construct calibration curves which may be used to calibrate the imaging device.

Abstract: An image input/output characteristic is computed from environmental information obtained by a temperature sensor, a photographic printing paper type read by an identification sensor, photographic printing paper characteristic information stored in a photographic printing paper characteristic memory, and previous calibration history information stored in a calibration history memory. Results of computation are output to a laser driver, and an amount of exposure or the like is corrected so as to calibrate a printer. As a result, a number of times that a calibration test pattern is printed and density is measured can be reduced, thereby improving working efficiency and saving photosensitive materials.

Abstract: A method embodiment of the invention tests revisions made to printer graphics interpreter software. A test suite of POSTSCRIPT, PCL, or other high-level printer language is input to a production version of a printer's internal interpreter software. A first bit-map is generated by the interpreter that is normally used to control each pixel in the printing of a page. The same test suite is fed to a work-in-progress revision of the printer's internal interpreter software. A second bit-map is generated. The first and second bit-maps are subtracted from one another. A difference bit-map is inspected. If only minor shifts of objects are noted, or if no differences at all are apparent, the work-in-progress revision is accepted as the new production standard. The second bit-map is used to replace the first. Otherwise, the work-in-progress revision of the printers internal interpreter software is reworked to correct the printing interpretation errors it was making.